| Sensient Flavors Limited | Sensient Technologies | chemicals | Environmental Violation | 2022 | UK-NRW | £0 |
| SL Recycling Ltd | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Stately Albion LTD | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Stormy Farm Limited | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Taylor Plant Ltd | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Tegfan Recycling | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Tegfan Recycling | | | Environmental Violation | 2022 | UK-NRW | £0 |
| The Eagles Hotel Ltd | | | Environmental Violation | 2022 | UK-NRW | £0 |
| The Eurogroup / Europest Environmental Services | | | Environmental Violation | 2022 | UK-NRW | £0 |
| The Range | | | Environmental Violation | 2022 | UK-NRW | £0 |
| The Slate Centre Ltd | | | Environmental Violation | 2022 | UK-NRW | £0 |
| The Solutions Factory Ltd | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Thomas Waste Management Limited | | | Environmental Violation | 2022 | UK-NRW | £0 |
| TIMET Waunarlwydd | Berkshire Hathaway | diversified | Environmental Violation | 2022 | UK-NRW | £0 |
| Toby carvery | Mitchells & Butlers PLC | restaurants and foodservice | Environmental Violation | 2022 | UK-NRW | £0 |
| Tom Prichard Contracting Ltd | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Tom Pritchard Contracting Ltd | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Tower Regeneration Limited | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Tradebe Healthcare National Limited | Tradebe | waste management and environmental services | Environmental Violation | 2022 | UK-NRW | £0 |
| Transcend Packaging Limited | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Trojan-Mek Limited | | | Environmental Violation | 2022 | UK-NRW | £0 |
| TXO Limited | | | Environmental Violation | 2022 | UK-NRW | £0 |
| UPM-Kymmene UK Ltd | UPM | paper and packaging | Environmental Violation | 2022 | UK-NRW | £0 |
| Valero Pembrokeshire Oil Terminal Ltd | Valero Energy | oil and gas | Environmental Violation | 2022 | UK-NRW | £0 |
| Walters U.K. Limited | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Warwick International Group Limited | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Whitehead Chartered Surveyors | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Woodvale Cars Ltd | | | Environmental Violation | 2022 | UK-NRW | £0 |
| WWT Llanelli Wetland Centre | | | Environmental Violation | 2022 | UK-NRW | £0 |
| Aggregates Express Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Aquadrain Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Ayjay Group Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| BAE Systems Global Combat Munitions Limited | BAE Systems | aerospace and military contracting | Environmental Violation | 2023 | UK-NRW | £0 |
| Beard Construction & Landscapes Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Borth and Ynyslas Golf Club Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Bryn Aggregates Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Bryn Recycling Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| C L James Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Caernarfon Commercial Hire Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Caldwell Construction Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Cardigan Metal Recycling Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Celsa Manufacturing (UK) Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Centregreat Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Checkfire Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Croenllwm Cyf | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Deliserve Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Ecosmart (Wales) Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Fiberight Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Fiberight Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Green Steel Works Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Hanson Paving & Development Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| I P Contracting and Plant Hire Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Intelligent Lifecycle Solutions | | | Environmental Violation | 2023 | UK-NRW | £0 |
| J Ellis Williams & Sons (Rhosneigr) Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| John Jones Civil Engineering and Groundworks Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| K and MNO Gibbon and Son | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Knights Brown Construction Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Llanishen Golf Club | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Llanmoor Development CO. Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| M.H.Davies Contractors Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Mansel Davies & Son Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Mark Hunter Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| McCarthy Plant (Bridgend) Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Morgans of Usk Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| National Grid | National Grid | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| National Grid Electricity Distribution Plc | National Grid | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| National Grid Electricity Distribution Plc | National Grid | utilities and power generation | Environmental Violation | 2023 | UK-NRW | £0 |
| Parry & Evans Recycling Services Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Pembrokeshire Coast National Park Authority | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Powys Environmental Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Rail Operations Group Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| REDI 205 Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Rexel UK Ltd | Rexel | wholesalers | Environmental Violation | 2023 | UK-NRW | £0 |
| Seer Construction Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Shotton Mill Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| SOS Plant Hire Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Taldrwst Cyf | | | Environmental Violation | 2023 | UK-NRW | £0 |
| The Range Home and Leisure Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Tilhill Forestry Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Tom Prichard Contracting Limited | | | Environmental Violation | 2023 | UK-NRW | £0 |
| V J Thomas & Son Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Wastesavers | | | Environmental Violation | 2023 | UK-NRW | £0 |
| WBH & CAD Evans and sons | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Williams Plant Hire Ltd | | | Environmental Violation | 2023 | UK-NRW | £0 |
| Castell Howell Foods | | | Environmental Violation | 2022 | UK-NRW | £0 |
| FRANK MERCER & SONS LIMITED | | | environmental violation | 2023 | UK-EA | £0 |
